Over the past decade the use and penetration of computational devices such as mobile or cellular phones and related technology, such as PDA's (personal digital assistants) has increased dramatically. Apart from providing voice communications, modem cell phones support SMS (short message services) by which a message of up to 160 characters of text may be entered, by means of a sender phone's keypad, or by a PC keyboard via the Internet, and transmitted over a telephone network for display on a receiver phone's display screen.
Various services associated with SMS have developed. According to one of these services text messages, with an associated addressee's cell phone number, may be sent from a content sender such as an Internet connected personal computer to an SMS web-server. The SMS web-server provides a gateway to a telephone network in order to deliver the message to the addressed cell phone where it is displayed in standard SMS format.
Although there have been no reported cases of successful interception of SMS messages via the SMS protocol under the GSM specifications, the use of SMS for transmitting sensitive information, such as financial transaction data, has been limited due to a perception that SMS transactions are potentially insecure. There have been solutions proposed for secure mobile banking that involve the use of a SIM toolkit whereby templates and security procedures are handled by modifying a cell phone user's SIM card. However, permission and agreement must be obtained from each carrier's SIM card provider. In order for a user to make use of a particular financial institution's SMS banking facility the user must purchase a SIM card from a provider with whom the financial institution has an agreement.